Thread cutter for sewing machines



June 24, B S v THREAD CUTTER FOR SEWING MACHINES Filed Aug. 13, 1945 2/ /62 A5 9 2.2 INVENTOR.

J1 #ys.

Patented june 24, 1947 THREAD CUTTER FOR SEWING MACHINES Arthur Blowers, Fort Plain, N. Y., assignor to Union Special Machine Company, Chicago, 111.,

a corporation of Illinois Application August 13, 1945, Serial No. 610,490

The invention relates to new and useful improvements in a thread cutter for sewing machines, and more particularly a cutter against which the stitching threads may be drawn by the operator for severing the same at the completion of a stitching operation.

An object of the invention is to provide a thread cutter for sewing machines including a cutting blade and an associated guide for directing the stitching threads onto the blade which is so constructed and mounted that the guide rests on the fabric during the stitching and moves down into contact with the work support as soon as the fabric passes from beneath the same so as to assure that the stitching threads will contact therewith and be directed onto the cutter and cut at the same time that the stitched fabric is moved laterally to remove it from the machine.

A further object of the invention is to provide a thread cutter of the above type wherein the guide supports the cutting blade and is so mounted and shaped as to move up automatically onto a fabric presented for stitching.

A still further object of the invention is to provide a cutter of the above type wherein the supporting bracket for the cutting blade and guide is mounted on the presser fOOt supporting means and moves up and down with the presser foot.

These and other objects will in part be obvious and will in part be hereinafter more fully described.

In the drawings which show one type of stitching mechanism with which the improved thread cutter may be used,

Figure l is a view showing more or less diagrammatically and in side elevation the improved thread cutter applied to an over-edge stitching mechanism;

vFigure 2 is a plan view of the presser foot and thread cutter;

Figure 3 is a View on a larger scale showing the presser foot and associated thread cutter in side elevation with the presser foot in engagement with the fabric being stitched;

Figure 4 is a view similar to Figure 3 but showing the presser foot raised and the thread guiding finger as moved downward into engagement with the work support;

Figure 5 is a view showing the work support and also in broken lines the thread guide and its relation to the needle throat, also showing the stitched fabric in full lines and in broken 4 Claims. (01. 1125252) 2 lines the fabric swung to bring the stitching threads into engagement with the cutter;

Figure 6 is a view showing the supporting bracket for the threadguide and cutting blade with a portion of the bracket broken away to show the guide in full lines;

Figure 7 is a view of the thread guide from the rear thereof and showing the manner of securing the cutting blade to the thread guide.

The invention has to do with a thread cutter for sewing machines and includes a cutting blade and a guide for directin the stitching threads onto the cutting blade. The cutting blade is rigidly attached to the thread guide. The thread guide and upported cutting blade are pivotally mounted on a supporting bracket so that the guide projects rearwardly from the bracket and is free to move up and down on its pivotal connection. The bracket is carried by the presser foot supporting means and moves up and down therewith. The guide, however, rests on the fabric while it is being stitched and when the fabric passes from beneath the same, it moves down into contact with the work support so that a thread guiding finger associated therewith will receive and direct the, stitching threads against the cutting blade when the stitched fabric is moved laterally for removing the same from the machine. The. improved thread cutter is adapted for use on any type of sewing machine. It may be used on a chain stitch .machine or a lockstitch machine, or on an over-edging machine.

The thread cutter as illustrated, is applied to an over-edging machine and will be described in detail in connection therewith. The over-edging machine as illustrated in the drawings includes a work support l carrying a throat plate 2 having a needle throat 3 therein, through which the needle 4 passes. Associated with the work support is a presser foot 5 which includes a supporting shank'fi to which a foot 1 is pivoted by a pivot bolt 8. The shank 6 is secured to a depending bar 9 carried by a presser foot lever l0. Cooperating with the needle beneath the work support is athread carrying looper and a thread carrying hook so that the looper thread loop is carried around the edge of the fabric by the hook and secured by the needle thread loops. The machine as illustrated in the drawings is shown more fully in the patent granted to A. S. Riviere on January 12, 1937, No. 2,067,680,- and further description of the stitching mechanism and associated devices is not thought necessary.

The thread cutter includes a supporting bracket II, which bracket is slotted at I2 to receive a clamping screw I3 which secures the shank 6 of the presser foot to the presser bar 9. A collar is placed on the clamping screw I3 and the bracket is firmly clamped against the collar by the head of the screw. This is for the purpose of offsetting the bracket from the presser foot as shown in Figure 2. This clamping of the bracket to the shank of the presser foot by the clamping screw described, may be'sufiicient for supporting the bracket, but in order to further ensure the rigidity of the support for the bracket on the presser foot shank the bracket has an opening I4 therethrough at the forward end thereof, and the pivot bolt 8 which pivots the presser foot I to the supporting shank is extended and passes through this opening I4. Thus the supporting bracket II is rigidly attached to the presser foot shank and will move up and down with the presser foot during the stitching operation, and when said presser foot is lifted at the completion of a stitching operation.

Pivotally mounted on this supporting bracket II is a thread guide I5. This thread guide I5 carries a cutting blade [6. As illustrated, the guide is provided with lugs I1 and I8 for securing the cutting blade firmly to the guide I5. It will be understood, of course, that other means for securing the cutting blade may be employed, it being essential, however, that the blade shall be rigidly attached to the guide.

The guide I5 is provided with a projecting finger I9. This finger extends rearwardly from the cutting edge 20 of the cutting blade IS. The upper face of the finger is tapered downwardly as indicated at 2| and terminates in a blunt edge 22. The guide I5 has an opening therethrough and is mounted on the pivot bolt 8 so that it may move freely thereon. When a fabric is being stitched it passes underneath the guide 85 and the guide is moved by its own weight on the pivotal support I4 so that the finger i9 rests on the fabric. This limits the downward movement of the guide so that when the fabric passes from beneath the guide, it will move down into contact with the work support. While the supporting bracket moves up and down with the presser foot, the rear end of the guide I5 will remain in contact with the fabric or work support, as shown in Figure 4.

At the completion of the stitching of an article indicated at F in Figure 5, the operator will continue to stitch until a series of enchained thread loops are formed, after which the machine is stopped and the fabric is removed by swinging it laterally away from the stitching line, as indicated at F in Figure 5. The chained thread loops or stitching threads will move up onto the finger I9 of the guide and thus be directed against the sharp cutting edge of the cutting blade and severed. This is accomplished simultaneously with the removal of the work from the machine. No matter whether the operator moves the work while on the surface of the work support or lifts it therefrom, still the stitching threads will be directed by this guide finger onto the cutting blade.

If the improved thread cutter be applied to any other type of sewing machine, it will be supported by the presser foot supporting means and will be so disposed relative to the presser foot that at the completion of the stitching of an article the moving of the same laterally for removing it from the machine will cause the stitching threads extending between the stitched article and the needle throat to contactvwith th guide, and the guide 4 will direct the stitching threads against the cutting edge of the cutting blade so that the threads will be severed.

It is obvious that many changes in the details of construction of the thread cutter and the manner of supporting the same may be made without departing from the spirit of the invention as set forth in the appended claims. It is essential, however, that the guide which carries the cutting 10 blade shall be free to move up and down so that it rests on the fabric during the stitching operation and will move down into engagement with the work support at the completion of the stitching operation.

I claim:

1. A thread chain severing device for sewing machines comprising a supporting bracket adapted to be attached to the sewing machine above the work support, a guide, a cutting blade carried by said guide, said guide having a thread directing finger projecting rearwardly from and beyond said blade, the upper edge of said finger extending forwardly past the edge of said blade so that threads moved along said finger will contact said blade, means for supporting said guide on said bracket so that the finger is free t move toward and away from said work support, said guide being disposed relative to the presser foot so that said finger will rest on the fabric section while stitching and will move down into engagement with the work support when the fabric section passes from beneath the finger and so that when the stitched fabric section is being removed from the machine, the stitching threads will engage said finger and be directed onto the cutting blade for the severing of the same.

2. A thread chain severing device for sewing machines comprising a supporting bracket adapted to be attached to the sewing machine above the work support, a guide, a cutting blade carried by said guide, said guide having a thread directing finger projecting rearwardly from and beyond said blade, the upper edge of said finger extending forwardly past the edge of said blade so that threads moved along said finger will contact said blade, means for supporting said guide on said bracket so that the finger is free to move toward and away from said work support, said guide being disposed relative to the presser foot so that said finger will rest on the fabric section while stitching and will move down into engagement with the work support when the fabric section passes from beneath the finger and so that when the stitched fabric section is being removed from the machine, the stitching threads will engage said finger and be directed onto the cutting blade for the severing of the same, said guide having its lower front edge portion curved upwardly so that said finger will move up onto a fabric section when presented for a stitching operation.

3 A thread chain severing device for sewing machines comprising a supporting bracket adapted to be attached to the sewing machine above the work support, a guide, a cutting blade carried by said guide, said guide having a thread directing finger projecting rearwardly from and beyond said blade, the upper edge of said finger extending forwardly past the edge of said blade so that threads moved along said finger will contact said blade, means for pivotally supporting said guide on said bracket so that the finger is free to turn on said ivot and move toward and away from the work support, said guide being disposed relative to the presser foot so that said finger will rest on the fabric section while stitching and will move down into engagement with the work support when the fabric section passes from beneath the same and so that when the stitched fabric section is being removed from the machine the stitching threads will engage said finger and be directed onto the cutting blade for the severing of the same.

4. A thread chain severing device for sewing machines comprising a supporting bracket adapted to be attached to the sewing machine above the work support, a guide, a cutting blade carried by said guide, said guide having a thread directing finger projecting rearwardly from and beyond said blade, the upper edge of said finger extending forwardly past the edge of said blade so that threads moved along said finger will contact said blade, means for pivotally supporting said guide on said bracket so that the finger is free to turn on said pivot and move toward and away from the work support, said guide being disposed relative to the presser foot so that said finger will rest on the fabric section while stitching and will move down into engagement with the work support when the fabric section passes from beneath the same and so that when the stitched fabric section is being removed from the machine the stitching threads will engage said finger and be directed onto the cutting blade for the severing of the same, said guide having its lower front edge portion curved upwardly so that the finger will move up onto a fabric section when presented for a stitching operation. ARTHUR BLOWERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,118,322 Weis Nov. 24, 1914 2,293,236 Anderson Aug. 18, 1942 2,318,843 Enos May 11, 1943 1,527,245 Willis Feb. 24, 1925 1,684,612 Willis Sept. 18, 1928 

